Carburetor metering valve



NW; 13, 1956 H. G. BOLTON 9 3 CARBURETOR METERING VALVE Filed July 10,1951 2 Sheets-Sheet l if x 17 13% 7 f 6 Z fnvenfr Harry 6 304% H. G.BOLTON CARBURETOR METERING VALVE 2 Sheets-Sheet 2 Filed July 10, 1951jazz/6721 57 flak-71y Gfialfan aw I3. 5 2x 2? United States PatentCARBURETOR METERING VALVE Harry G. Bolton, Decatur, Ill., assignor toBorg-Warner Corporation, Chicago, Ill., a corporation of IllinoisApplication July 10, 1951, Serial No. 235,951

2 Claims. (Cl. 137625.48)

This invention relates to carburetors, and more particularly to ametering valve arrangement for a twin or double barrel type carburetor.

Twin or double barrel carburetors are well known, the usual arrangementthereof being to supply the fuel needs of one half of the cylinders ofan engine through one intake manifold connected to one barrel and of theother half of the cylinders through a separate intake manifold connectedto the other barrel of the carburetor. A primary difficulty, however, inthis type of arrangement is that of supplying equal amounts of fuelsimultaneously to the two intake manifolds so that uniform engineperformance is obtained from all cylinders. Also, pulsations occurringin one intake manifold may affect adversely the fuel supply to the otherintake manifold, since these pulsations may be communicated through thecoin mon float valve chamber.

Objects of the present invention are to provide a new and improveddouble barrel type carburetor and more particularly an improved meteringvalve arrangement whereby uniformity of fuel supply to each barrel ismaintained throughout the full range of adjustment of a single meteringvalveand whereby cross effects due to pulsations occurring in one barrelor intake manifold which may be communicated to the other barrel orintake manifold are substantially eliminated.

In accordance with one embodiment of this invention as applied to agenerally conventional, double barrel type carburetor, a single meteringvalve is employed which is located in the float valve chamber and is incommunication therewith at one end. As the valve is moved toward openposition an annular passage is gradually eX- posed, to opposite sides ofwhich passage are connected ports leading to the respective nozzlesassociated with each of the carburetor barrels. The valve is arranged sothat communication between the two ports is obstructed by the valve bodyalthough communication between a port and the float chamber isrelatively unimpeded except for the normal metering action of the valve.The valve is also so arranged that pulsations present in one carburetorbarrel or port are dissipated before reaching the other port or barrelsince such pulsations pass through the float valve chamber and the fuelcontained therein and are substantially absorbed thereby.

Othe objects and advantages of the present invention will be apparentfrom the following detailed description thereof taken in conjunctionwith the drawings wherein:

Fig. l is a sectional view, taken substantially along the line 1-1 ofFig. 3, of a double barrel type carburetor constructed in accordancewith one embodiment of this invention;

Fig. 2 is a horizontal, cross sectional view, taken substantially alongthe line 22 of Fig. l, and showing to advantage the double barrelarrangement;

Fig. 3 is an end view with the float valve chamber broken away to showthe metering valve arrangement of this invention, the view being takenfrom the air intake end of the carburetor;

Fig. 4 is a vertical sectional view taken along line 4 4 of Fig. 3; and

Fig. 5 is an enlarged, detailed sectional view of the metering valveshown in Figs. 3 and 4.

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Referring now to the drawings, it will be seen that the twin carburetorof this invention comprises a double barrel housing 10 and a floatchamber 11 mounted on the underside of the barrel housing 10. Twoparallel extending barrels 12 and 13 are formed in the barrel housing 10and are arranged to be located in horizontal relation to the entireengine (not shown) with which the carburetor is to be associated, thecarburetor being of the side delivery type. Air intake ports are formedat the left ends of the two barrels, as viewed in Figs. 1 and 2, whiledischarge ports, adapted to be connected to the intake manifoldsassociated with the engine, are located at the right ends of the twobarrels. Conventional choke valves 14 and 15 are disposed within theleft end portions of the barrels 12 and 13, respectively, while throttlevalves 16 and 17, respectively, are disposed in the right end portionsof these two barrels, as shown in Fig. 2.

Liquid fuel is supplied to the float chamber 11 through a port 20 whichcommunicates with the chamber through a passage 21 formed in thecarburetor housing. The quantity of fuel in chamber 11 is regulated byfloat valve assembly 22, the opening of which valve is controlled by afloat 23, located within chamber 11 and floating on the surface of thefuel therein. When the level of the .fuel drops below a predeterminedvalue, the weighted valve member 22a is permitted to drop downwardly ashort distance and thereby to open the lower end of the passage 21 intothe chamber 11 to maintain the fuel supply therein.

A pair of idling valves 24 and 25 are associated, respectively, with thebarrels 12 and 13 and control the admission into the throttle chamberportions thereof of fuel during the idling operation of the engine withwhich this carburetor is intended to be associated. A pair of maindischarge nozzles 26 and 27 have their discharge ends locatedrespectively in the venturi portions of the barrels 12 and 13 and aresupplied with fuel from the chamber 11 in a manner to be describedhereinafter. The carburetor so far described is conventional and,accordingly, it is believed, that no more detailed description thereofis necessary.

In accordance with the present invention, the fuel supplied to thenozzles 26 and 27 is closely and uniformly controlled through a novelmetering valve arrangement 30 whereby not only is the amount of fuelsupplied to both nozzles made equal, but also pulsations which may occurin one side of the carburetor system are substantially prevented frombeing communicated to the other side thereof. Referring particularly toFigs. 3, 4 and 5 it will be seen that the novel metering valvearrangement 30 of this invention is located in the lower mid portion ofa block portion 31 of the carburetor, the portion 31 being disposedwithin the float valve chamber 11 and integrally formed with theunderside of housing 10. For tion 31 has a vertically disposed passageor valve chamber 32 formed therethrough, the lower portion 32a of whichis enlarged somewhat and threaded to receive the threaded outerperiphery of the lower end of a valve holder 33. Valve holder 33 is ofgenerally cylindrical configuration and the upper portion or stem 33b issubstantially reduced in diameter as compared with the lower terminalportion. The lower end 33a extends beyond the bottom wall of floatchamber 11, which is suitably apertured, and is provided with atransverse slot 330 at its lower extremity to receive a screwdriver tip,for example, whereby the position of the valve stem 33b in the chamber32 may be adjusted.

A sleeve valve 34 is carried by the stem 33b, the lower end of thesleeve valve 34 resting on a shoulder 33d formed at the point ofreduction in diameter of the valve holder. It will be noted that theouter diameter of the major portion of the sleeve valve 34 is madesufiiciently great so that a close fit is had between the outer portionthereof and the inner wall of the chamber 32, while the inner diameterof the sleeve 34 is made substantially greater than the outer peripheryof the reduced stem portion 33b. In this manner angular misalignment ofthe valve stem without consequent binding of the valve sleeve in thepassage 32 is permitted. There can also be lateral misalignment betweenthe sleeve and the valve stem 33b because of this clearance. In one typeof carburetor constructed in accordance with this invention thisclearance was made to be of the order of .015 inch.

Sleeve valve 34 is retained in position against the shoulder 33d by anannular, dished-type spring washer 35, the underside of which washerbears against the upper end of the sleeve valve, the spring washer 35being in turn retained by a ring 36 bearing against the upper sidethereof and held in place by a rivet 37 or other suitable means carriedby the upper end of the valve stem portion 33!).

Referring now particularly to Fig. 3, it will be noted that fromdiametrically opposite sides of the upper portion of valve chamber 32there extend two passages 40 and 41, these passages communicating attheir ends remote from the chamber 32 with the nozzle chambers 42 and 43of the nozzles 26 and 27, respectively. The inner ends of these passages40 and 41 are sharply reduced to provide restricted orifices 40a and41a, respectively, at the points of communication with the chamber 32.By selecting the degree of restriction of orifices 40a and 41a, themaximum port opening may be predetermined irrespective of the maximumopening of the metering valve 30.

When the valve holder 33 is in its uppermost position, as viewed in Fig.3, that is, is screwed fully into the housing block 31, the sleeve valve34 completely obstructs the restricted inner ends of the passages 40 and41. However, the upper end of the sleeve valve 34 is tapered, asindicated at 34a, to provide a valving surface so that by withdrawingthe valve holder slightly, the tapered or valving surface 34a may beplaced in communication with the ports 40a and 41a, the degree of valveopening being obviously determined by the extent to which the valve 34is moved downwardly, as viewed in Figs. 3 and 4.

From the foregoing it will be evident that fuel in the float valvechamber 11 is, when metering valve 30 is opening, communicated to themain nozzles 26 and 27 through an annular passage 34!; having a righttriangular cross-section. It will be evident, further that the passage34b from port 40a to port 41a is circuitous and that the line of leastresistance is normally from one port through the triangularcross-section passage 34b into the chamber 11 and from thence downwardand into the other port. Accordingly, pulsations occurring in one nozzlesupply line will be both obstructed by the valve 34 and also dissipatedin passing through the float valve chamber 11. In practice it has beenfound that this arrangement substantially eliminates pulsations from onebarrel of the carburetor affecting the other barrel of the carburetor,while ensuring uniform delivery of fuel to both barrels.

While this invention has been described particularly in connection witha double barrel type carburetor, because this is the most commonapplication of this invention, my tests have indicated that it isequally suitable for carburetors having more than two barrels, it beingrequircd only that an additional port be provided in the side of thevalve chamber for each additional barrel. Preferably, regardless of thenumber of ports, the ports should be equally spaced from each other.Also, while this invention has been described in connection with anarrangement where the metering valve supplied the total fuelrequirements of the carburetor, the metering valve arrangement may alsobe used only as a supplementary supply, as for example, where fixed jetsare fed directly from the bowl of the carburetor and supply the majorportion of the total fuel flow. These variations and other Y 4combinations will be readily apparent to those skilled in the art.

Where herein the various elements of the carburetor of this inventionhave been referred to as being located in a right or a left position, orin an upper or a lower position, it will be understood that this hasbeen solely for the purpose of facilitating description and that suchreferences relate only to the relative positions of the parts as shownin the accompanying drawings.

While but one embodiment of this invention has been shown and described,it will be understood that many changes and modifications in addition tothose referred to herein may be made without departing from the spiritor scope of the present invention.

What is claimed is:

1. A metering valve assembly for a carburetor having a fuel feedingnozzle associated therewith and a reservoir for fuel, said meteringvalve assembly including means defining a valve chamber having one endthereof adapted for communication with said reservoir andcircumferentially spaced ports formed in said chamber and spaced fromsaid one end, a sleeve valve journalled in said chamber and having aconically tapered metering surface formed thereon adjacent to said oneend for controlling the flow of fuel through said chamber to said ports,said tapered metering surface and said adjacent end wall of said chamberdefining an annular passage of generally triangular cross-section, thewider end of which passage adapted for communication with said reservoirand the narrower end whereof may be placed in communicationsimultaneously and equally with each of said ports, and means foradjusting the position of said valving surface with respect to saidports including a valve stem surrounded by said sleeve and spacedtherefrom, said stem having an enlarged portion provided with screwthreads and resilient means for holding said sleeve valve on said valvestem by pressure on the ends of said sleeve valve, whereby said sleevevalve may be moved axially by rotation of said screw threaded portionand said sleeve valve is laterally movable relative to said stem.

2. A metering valve assembly for a carburetor having a fuel feedingnozzle associated therewith and a reservoir for fuel, said meteringvalve assembly including means defining a valve chamber having one endthereof adapted for communication with said reservoir andcircumferentially spaced ports formed in said chamber and spaced fromsaid one end, a sleeve valve journalled in said chamber and having aconically tapered metering surface formed thereon adjacent to said oneend for controlling the flow of fuel through said chamber to said ports,said tapered metering surface and said adjacent end wall of said chamberdefining an annular passage of generally triangular cross-section, thewider end of which passage is adapted for communication with saidreservoir and the narrow end whereof may be placed in communicationsimultaneously and equally with each of said ports, and means foradjusting the position of said valving surface with respect to saidports including a valve stem surrounded by said sleeve valve and spacedtherefrom, and resilient means for holding said sleeve valve on saidvalve stem by pressure on the ends of said sleeve valve, whereby saidsleeve valve is laterally movable relative to said stem.

References Cited in the file of this patent UNITED STATES PATENTS112,216 Broadbent et al Feb. 20, 1871 817,153 Barr Apr. 10, 19061,186,797 Kingston June 13, 1916 1,536,415 Beck et al. May 5, 19252,016,878 Vickers Oct. 8, 1935 2,209,442 Bufiington July 30, 19402,374,336 DArcey Apr. 24, 1945 2,391,898 Hobbs Ian. 1, 1946 2,464,328Mallory Mar. 15, 1949

